Illumination control system



Feb. 21, 1939. J. c. BATCHELOR 4 0 ILLUMINATION CONTROL SYSTEM Filed se t. 9, 19s? 2 Sheets-Sheet 1 IIHO'I 0'00".

INVENTOR JOHN C. 5/4 7'617540/3 BY fimbpwmmm QEMWJA ATTO R N EYS Feb. 21, 1939. J, c BATCHELOR 2,148,007

ILLUMINAT I ON CONTROL SYSTEM Filed Sept. 9, 1957 2 Sheets-Sheet 2 l NVENTOR JOHN C. BATCH/51w? ATTO R N EYS Patented Feb. 21, 1939 UNITED STATES ILLUMINATION CONTROL SYSTEM John 0. Batchelor, Hastings (in-Hudson, N. Y.,

assignor to Aifiliated Industrial Corporation Application September 9, 1937, Serial No. 163,107

Claims.

This invention relates generally to a method and apparatus for producing alternate and successive pulses of light which may diifer from one another in one or more of the characteristics, color, intensity, duration, and location of the sources thereof. More particularly, the invention provides a method and apparatus for controlling electric lights of different colors to alternately and successively illuminate a surface containing representations or figures in complementary colors, to create an illusion of motion or animation of such representations, without the annoying accompaniment of color flicker.

The invention may be used to great advantage in connection with advertising displays, signs, and the like, for. the production of illusions of motion in fixed pictorial or graphical representations in complementary colors in a plurality of positions on a neutral-colored background. By illuminating such representations alternately and successively with light pulses of different colors chromatically related to the colors of the representations, effects may be obtained which are both striking and pleasing to the eye.

Heretofore, in the illuminated advertising sign art employing one or more pairs of complementary colored light sources to illuminate chromatically related representations on a sign, it has been customary to effect complete modulation of each source between total extinction and full luminosity. To accomplish this mode of operation with gas discharge tube light sources, it has'been the universal practice to employ exclusively tubes of the low-pressure type. Such tubes, although easily re-started, are known to be of relatively low efliciency as light sources, as compared with high be restarted as a glow discharge, on account of.

the high pressure of the mercury vapor. Such condition continues until the pressure is once more reduced by cooling and consequent condensation of the mercury.

The devices heretofore known, therefore, are far less efllcient than they would be were it possible to employ high-pressure tubes.

It is a well known fact that whereas low-pressure gas discharge tubes having a red color characteristic, such as neon tubes, give the impression of a substantial amount of rich red light, lowpressure gas-discharge tubes having a minus-red or cyan color characteristic give the impression, of a pale or weak light. Hence when the two types are used in combination, theobserver receives an impression of unbalance and color flicker, and a paucity of richpurples in the neutral portions of the representation. The strong cyan light of high-pressure tubes or mercury vapor tubes, on the other hand, is not open to this objection. 1

My invention is based largely on the discovery that more striking and more pleasing results can be obtained by controlling a first light source of one color and of a certain full luminosity, to effect periodic or intermittent modulation thereof from total extinction to full luminosity, and alternately therewith, controlling a second light source of a different color and of a substantially greater full luminosity than that of the first, to effect modulation thereof from partial luminosity to full luminosity. The intermittent decrease in luminosity of the second source is preferably so selected as to be of the order of the full luminosity of the first source.

Without definitely subscribing to a particular theory of operation, I believe that the results obtained as described above depend primarily upon the contrast in luminosity of the representations between the two phases of the operating cycle,

. and only secondarily upon the absolute value of the luminosity.

Furthermore, I have observed that when exactly equal quantities of light of substantially complementary colors are employed, as produced by methods heretofore known, a substantial amount ofcolor flicker is produced from and upon the portions of the display which are intended to be neutral. This is believed to be due primarily to thechange of the sensation value of the light with change of color, due to a shifting of the stimulus from one set of light-sensitive elements within the human eye to another. And this phenomenon may occur although the actinic value of the light on the neutral ..background is substantially constant.

As the result of my discovery that one of the colored light sources may be continuously excited and illuminated, it becomes possible to use a highefliciency, high-pressure gas discharge tube, a mercury vapor tube, for example, as one of the sources of colored light in the illumination system under discussion, since it is no longer necessary tostart such tube from a totally extinguished condition. Thus, it is merely necessary to effect modulation of such high-pressure tube from partial luminosity to full luminosity, preferably substantially instantaneously.

To practice the invention with a specific embodiment, at least two gas discharge tubes are provided, including a low-pressure tube and a high-pressure tube. Suitable sources of electric energy are provided, and the tubes are arranged to be energized or excited in associated electric circuits by appropriate control equipment. The low-pressure tube is operated to effect modulation thereof from total extinction to full luminosity, and the high-pressure tube is operated alternately with the low-pressure tube to effect modulation of the high-pressure tube from its full luminosity to substantially less than its full luminosity. Thus, the high-pressure tube is continuously excited and never totally extinguished.

The invention will be more fully understood from the following description, considered with the accompanying drawings. In these drawings:

Fig. 1 illustrates schematically a pair of tubes and associated electric control circuits and apparatus, arranged to produce alternate and successive pulses of light;

Fig. 2 illustrates schematically an arrangement similar to that of Fig. 1, but in which more than one pair of luminous tubes is employed;

Fig. 3 illustrates schematically an arrangement employing more than a pair of luminous tubes, with certain modifications of the control circuits.

Referring to Fig. 1, I have provided the lowpressure luminous discharge tube I connected to the output terminals 3 and 4 of the transformer 2. The high-pressure luminous discharge tube 5 is connected to the output terminals 1 and 8 of the autotransformer 5.

A mechanical contactor 9 is provided having two sets of contacts I0, I 8 and II, I9, adapted to be alternately and successively closed by the operation of the cam |2 driven by the motor I3. A source of alternating current energy indicated by the plug I4 has one side connected directly to the input terminal ll of the transformer 6, and to the input terminal I5 of the transformer 2. The other side of the plug I4 is connected through the resistor 20 to the remaining input terminal 2| of the autotransformer 6. The latter side of the plug I4 is also connected through the contacts I3 and II of the contactor 9 to the input terminal I6 of the transformer 2. The contacts I and I8 are connected respectively to the terminals 22 and 23 of the resistor 20 in such fashion that the resistor 20 is effectively short-circuited at such times as the contacts I0 and I8 are closed.

From the above description of the circuit arrangements and connections, it is evident that when the cam I2 is driven by the motor I3, the full voltage of the source I4 is applied through the contacts I9 and I I to the primary winding of the transformer 2 during one half of each revolution, and that during the other half revolution, when the contacts II and I9 are open, no voltage is applied to the transformer 2. It is further evident that during the first half revolution of the cam I2, when the contacts I0 .nd I8 are open, the voltage of the source I4 is applied through the resistor 20 to the terminals I1 and 2| of the autotransformer 6, the voltage at the transformer 6 being thus reduced below the source voltage by the voltage drop in the resistor 20; and that during the succeeding half revolution, when the contacts I0 and I8 are closed, the voltage of the source I4 is applied directly to the terminals I1 and 2| of the autotransformer Ii. Thus, due to the connections of the gas discharge tubes I and to the transformers 2 and 6 respectively, as above described, the tube I is subjected to successive and intermittent excitation, varying substantially instantaneously from a zero value to a predetermined value; whereas the tube 5 is subjected to successive and intermittent excitation varying substantially instantaneously from a greater predetermined value to a lesser predetermined value, the intermittent decrease being determined by choice of the resistor 20. Since the function of the resistor 20 is to provide a voltage drop, any other form of impedance, such as a choke coil, may equally well be employed. I

A display surface or area is shown at 24, having a neutral background 21 and having, for example, a plurality of concentric rings 25 and 26 in complementary colors; for example, the rings 25 may be cyan, otherwise known as minus red, and the rings 26', concentric and alternate with the rings 25, may be red. The tube I in the embodiment shown may be a conventional low-pressure luminous gas discharge tube containing a gas having a characteristic red or redorange glow; the gas neon, for example. The luminous discharge tube 5 is preferably of the high-pressure high-efficiency type of mercury vapor tube which may be filled, for example, with argon at a relatively low pressure, and may contain a measured quantity of mercury such that, when normal operating temperature has been reached, the pressure of the mercury vaporized within the tube may be of the order of, for example, one-half atmosphere.

2 represents a modification of the apparatus 0: Fig. 1 in that a relatively large display surface 28 is provided having a length greater than that which can be illuminated conveniently by a single pair of discharge tubes I and 5. Three similar luminous discharge tubes I, 29 and 30 are provided, connected to the secondary windings of the transformers 2, 3| and 32, respectively. The primary windings 35, 33 and 34 of the transformers 2, 3| and 32 are connected in parallel, and the three primaries 35, 33 and 34 are adapted to be excited intermittently by energy derived from a source indicated by the plug I4 through the contacts II and I9 of the contactor 9,

The transformer 6, which supplies the tube 5, is adapted to receive continuous partial excitation from the plug I4 through the resistor 20 during the time when the contacts Ill and I8 are open, and full excitation through the contacts III and I8 in parallel with the resistor 20 when those contacts are closed. Energy is supplied to the luminous discharge tubes 38 and 39 by the transformers 40 and 4|, the tubes 38 and 39 being similarly connected and similar to the tube 5, and the transformers 40 and 4| being similarly connectedoand similar to the transformer 6. The transformers 40 and 4| are likewise adapted to receive continuous partial excitation through the resistors 36 and 31, respectively, and intermittent full excitation through the contacts 42, 43 and 44, 45, respectively.

The display surface 28 is provided, for example, with the neutral background 21, the cyan representation 46 and the red representation 41 comprising alternate blooks of the respective colors disposed in a manner such that the illusion of continuous motion is created along their length.

Under certain conditions, it is desirable that the cyan illumination be intermittently reduced to as low a value as possible. Such conditions may arise when, for example, the greater part, geometrically, of the surface representations are cyan but it is desired that the dominant color of the display be red. In the embodiment shown in the figures, this requires that the mercury vapor tube 5 of Fig. 1, orthe tubes 5, 38, and 39 of Fig. 2, have their luminosities intermittently decreased as nearly to the point of extinction as possible. control circuits of Fig. 2 are provided, including particularly the separate contact pairs Ill-48, 43-42, and 45-44; and the separate resistors 20, 36, and 31, connected as shown.- This separation of the control circuits prevents any irregularity in the operation of any one of the cyan tubes from being reflected as an inverse irregularity in another of those tubes.

When, on the other hand, aflsubstantial continuous residual cyan light is either unobjectionable or desirable, it is feasible to maintain thecontinuous cyan luminosity, and therefore the continuous excitation of the mercury vapor tubes, at a relatively high level. In such case, the effect of reflection of irregularities in the operation of one tube into another is relatively small, and the contact pairs Ill-I8, 43-42, and 45- may safely be replaced by a single contact pair, the resistors 20, 36, and 31 being similarly replaced by a single resistor of appropriate value. This arrangement is shown in Fig. 3, wherein the transformers 2, 3| and 32 for the tubes l, 29 and 30, respectively, are excited and controlled by energy from the source l4 through the contacts II and Ill. The transformers 6, and ti for the tubes 5, 38 and 39are similarly connected in parallel and are adapted to receive continuous partial excitation through the single resistor 48 and intermittent full excitation through the contacts 49 and 50, in parallel with the resistor 48 and actuated by the cam I2 of the contactor 9.

By employing the arrangements of my invention it becomes possible to take advantage of the relatively low illuminating and atmospheric penetrating power of light of the general hue cyan. Thus, though the tube 5 is at all times excited to a point safely above the extinction point, its luminosity, when reduced in intensity by excitation through the resistor 20, may be made of such low value that the visible illumination of the disphases of the cycle shall be equal.

One of the uses for which the arrangements and methods of my invention are well adapted, is to reduce as far as possible the color flicker on the neutral portion 21 of the surface 24, and I have found it possible to reduce the amount of this color flicker very materially below the level possible by methods heretofore known. To this end I employ a relatively large quantity of cyan light to illuminate the cyan concentric rings 25, and intermittently reduce the amount of this cyan light approximately to'one-third its value at full luminosity, providing at the same time red light in approximately the amount by which the cyan light is reduced; that is to say, the maxi- It is for such case that the separate mum value of the red light is about two-thirds the maximumyalue of the cyan light or about twice its reduced value. By this choice of light values I have found that a neutral portion 21, capable of reflecting substantially equally both cyan and red light, will present the appearance I of substantially constant illumination.

I may still further vary the lighting effects obtainable by controlling the illumination from the two sources, and therefore the luminosity in the two colors, in other ways. For example, I may place the cyan source at one distance from the surface representation and the red source at a different distance. I may likewise place these sources at different angles with respect to the surface. Furthermore, I may alter the duration of the different-colored pulses. This may most easily be accomplished by the use of a long-arc cam for one set of contacts and a short-arc cam for the other set of contacts.

Though I have described my invention inconnection with gas discharge tubes, it is obvious that certain of its advantages may be achieved by the use of different-colored light sources of other types. Furthermore, while I have described the invention in connection with a display system, it is, of course, applicable to any system in which two or more sets of light pulses, differing in any particular, are alternately and intermittently produced.

Having now described my invention, I claim:

1. In a system of illumination utilizing at least two electrically actuated light sources, one of said sources being of the high-pressure dischargetube type and the other of said sources being of a different type, the method of producing alternate and successive pulses of light which comprises continuously exciting said high-pressure tube source to eifect continuous illumination thereof at at least partial luminosity, exciting said highpressure tube source to effect periodic modulation thereof from said partial luminosity to its full luminosity, and alternately therewith exciting said other light source to effect periodic modulation thereof from total extinction to its full luminosity.

2. In a system of illumination utilizing at least two electrically actuated gas-discharge tube light sources, one of the high-pressure type and another of the low-pressure type, the high-preasure tube source having a substantially greater intensity. at full luminosity than the low-pressure tube source at full luminosity, the combination which comprises means for successively and intermittently exciting the low-pressure tube source r.

to effect modulation thereof from total extinction to its full luminosity, means for continuously exciting the high-pressure tube source to effect continuous illumination thereof at at least partial luminosity, and means for exciting said highpressure tube source, alternately of the excitation of said low-pressure tube source, to effect modulation of said high-pressure tube source from said partial luminosity to its full luminosity.

. 3. In a system of illumination utilizing at least two electrically actuated gas-discharge tube light sources, one of the high-pressure type and another of the low-pressure type, the high-pressure tube source having a substantially greater intensity at full luminosity than the low-pressure tube source at full luminosity, the combination which comprises means for successivelyand intermittently exciting the low-pressure tube source to effect periodic modulation thereof from total'extinction to its full luminosity, means for con- 1 producing alternate and successive pulses of light,

tinuously exciting the high-pressure tube light sourceto effect continuous illumination thereof at at least partial luminosity, and means for exciting said high-pressure tube source, alternately of the excitation-of said low-pressure tube source, to effect periodic modulation of said high-pressure tube source from said partial luminosity to its full luminosity, the intermittent change in luminosity of said high-pressure tube source from said partial luminosity to said full luminosity being of the order of the full luminosity of said lowpressure tube source.

4. In a system of illumination utilizing at least two electrically actuated gas-discharge tube light sources, one of the high-pressure type and another of the low-pressure type, the high-pressure tube source having a substantially greater intensity at full luminosity than the low-pressure tube source at full luminosity, the method of producing alternate and successive pulses of light, which comprises continuously exciting the high-pressure tube source to effect continuous illumination thereof at at least partial luminosity, successively and intermittently exciting the lowpressure tube source to effect modulation thereof from total extinction to its full luminosity, and alternately therewith exciting the high-pressure tube source to effect modulation thereof from said partial luminosity to its full luminosity.

5. In a system of illumination utilizing at least two electrically actuated gas-discharge tube light sources, one of the high-pressure type and another of the low-pressure type, the high-pressure tube source having a substantially greater intensity at full luminosity than the low-pressure tube source at full luminosity, the method of which comprises continuously exciting the highpressure tube source to effect continuous illumination thereof at at least partial luminosity, successively and intermittently exciting the lowpressure tube source to effect periodic modulation thereof from total extinction to its full luminosity, alternately therewith exciting the high-pressure tube light source to effect periodic modulation thereof from said partial luminosity to its full luminosity, and limiting the intermittent decrease in luminosity of the high-pressure tube source to the order of the full luminosity of the low-pressure tube source.

6. In the art of alternate and successive illumination of objects by at least two light-sources of different characteristics, the method of utilizing a high-efficiency high-pressure discharge tube as one of said light-sources and a low-pressure gas-discharge tube as another of said lightsources, which comprises successively exciting said low-pressure tube to effect modulation of the light thereof from extinction to full luminosity thereof, continuously exciting said highpressure tube at at least partial luminosity of -the light thereof, and successively exciting said high-pressure tube, alternately of the excitation of said low-pressure tube, to effect modulation of the light thereof from said partial luminosity to the full luminosity thereof.

'7. In the art of alternate and successive illumination of objects by at least two light-sources of complementary colors, the method of utilizing a high-efficiency high-pressure mercury-vapor discharge tube of cyan color characteristic as one of said light sources and a low-pressure neon gasdischarge tube of red color characteristic as another of said light-sources which comprises successively exciting said neon gas-discharge tube to effect modulation of the red light thereof from extinction to full luminosity thereof, continuously exciting said mercury-vapor tube at at least partial luminosity of the cyan light thereof, and successively exciting said mercury-vapor tube, alternately of the excitation of said neon gas-discharge tube, to effect modulation of the cyan light thereof from said partial luminosity to the full luminosity thereof.

8. In the art of alternate and successive illumination of representations having at least two different visual characteristics by at least two light-sources of characteristics corresponding to the characteristics of said representations, the method of utilizing a high-efficiency high-pressure discharge tube as one of said light sources and a low-pressure gas-discharge tube as another of said light-sources which comprises successively exciting said low-pressure tube to effect periodic modulation of the light thereof from extinction to full luminosity thereof, continuously exciting said high-pressure tube at at least partial luminosity of the light thereof, successively exciting said high-pressure tube, alternately of the excitation of said low-pressure tube, to effect periodic modulation of the light thereof from said partial luminosity to the full luminosity thereof, and illuminating said representations with the light from said light-sources.

9. In the art of alternate and successive illumination of representations in at least two complementary colors by at least two light-sources of corresponding complementary colors, the method of utilizing a high-efficiency mercury-vapor discharge tube of cyan color characteristic as one of said light sources and a low-pressure neon gas-discharge tube of red color characteristic as another of said light-sources which comprises successively exciting said neon gas-discharge tube to effect periodic modulation of the red light thereof from extinction to full luminosity thereof, continuously exciting said mercury-vapor tube at at least partial luminosity of the cyan light thereof, successively exciting said mercury-vapor tube, alternately of the excitation of said lowpressure tube, to effect periodic modulation of the cyan light thereof from said partial luminosity to the full luminosity thereof, and illuminating said representations with the light from said mercury-vapor tube and said neon tube.

10. In an electrical display system having a surface bearing representations in complementary red and cyan colors, and illumined by a lowpressure gas-discharge tube source of light of a red color and a relatively high-pressure discharge tube source of light of a cyan color, the combination of means for successively exciting said low-pressure tube to effect modulation of the red light thereof from extinction to full luminosity of said tube, means for continuously exciting said high-pressure tube to produce continuous cyan light at at least partial luminosity of said tube, and means for successively exciting said high-pressure tube, alternately of the excitation of said low-pressure tube, to effect modulation of the cyan light thereof from said partial luminosity to full luminosity of said tube, said full luminosity being substantially greater than the full luminosity of said low-pressure tube.

11. In an electrical display system having a surface bearing representations in complementary red and cyan colors, and illumined by a low-pressure gas-discharge tube source of light of a red color and a relatively high-pressure gasdischarge tube source of light of a cyan color, the

combination of means for successively exciting said low-pressure tube to effect modulation of the red light thereof from extinction to full luminosity of said tube, means for continuously exciting said high-pressure tube to produce continuous cyan light at at least partial luminosity of said tube, and means for successively exciting said high-pressure tube, alternately of the excitation of said low-pressure tube, to effect modulation of the cyan light thereof from said partial luminosity to full luminosity of said tube, said full luminosity being substantially greater than the full luminosity of said low-pressure tube, and the intermittent change in luminosity of said'highpressure tube being of the same order as the full luminosity of said low-pressure tube.

12. In an electrical display system having a surface bearing representations of different color characteristics, and illumined by a low-pressure s-discharge tube light-source and a relatively high-pressure discharge tube light-source, said sources having color characteristics correspondmg to those of said representations, the combination of means for successively exciting said lowpressure tube to effect periodic modulation of the light thereof from extinction to full luminosity of said tube, means for continuously exciting said high-pressure tube to produce continuous light at at least partial luminosity of said tube, and means for successively exciting said high-pressure tube, alternately of the excitation of said low-pressure tube, to effect modulation of the light thereof from said partial luminosity to.

' full luminosity of said tube, said full luminosity being substantially greater than the full luminosity of said low-pressure tube.

13. In an electrical display system having a surface bearing representations of different color characteristics, and illumined by a low-pressure gas-discharge tube light-source and a relatively high-pressure discharge tubev light-source, said sources having color characteristics correspond-J ing to those of said representations, the combination of means for successively exciting said low-fipressure tube to effect periodic modulation of the light thereof from extinction to full luminosity of said tube, means for continuously exciting said high-pressure tube to produce continuous light at at least partial luminosity of said tube, and means for successively exciting said high-pres sure tube, alternately of the excitation of said low-pressure tube, to effect modulation of the light thereof from said partial luminosity to full luminosity of said tube, said full luminosity being substantially greater than the full luminosity of said low-pressure tube, and the intermittent change in luminosity of said high-pressure tube being of the same order as the full luminosity of said low-pressure tube.

14.-In an electrical system for alternately and successively operating at least two different gasdischarge tubes, the combination of a first transformer having input and output terminals, a circuit including said input terminals arranged for connection to a source of alternating current energy, a low-pressure gas-discharge tube connected in a circuit including said output terminals, a second transformer having input and output terminals, the second-named input terminals being arranged for connection to said source of alternating current energy, an impedance connected in series with the second-named input terminals and said source, a high-pressure gas-discharge tube connected in a circuit including the output termin'als of said second transformer, means for periodically exciting said first transformer and lowpressure tube at predetermined intervals from said source, means for exciting said second transformer and said high-pressure tube from said source, and means for periodically short-circuiting said impedance during the periods of extinction of said low-pressure tube.

15. In an electrical system for alternately and successively operating gas-discharge tubes of at least two different types, the combination of a first plurality of similar transformers having input and output terminals, circuits including said input terminals arranged for connection to a source of alternating current energy, a plurality of similar low-pressure gas-discharge tubes arranged in circuits including the output terminals of said first-named transformers, a second plurality of similar transformers having input and output terminals, circuits including the input terminals of said second-named transformers arranged for connection to said source, a plurality of similar impedances arranged in series with 

